• The Korean Journal of Physiology and Pharmacology
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• 제18권2호
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• pp.109-120
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• 2014

The epothilones are a class of microtubule inhibitors that exhibit a strong antitumor activity. UTD2 is a novel epothilone analog generated by genetic manipulation of the polyketide biosynthetic gene cluster. This study investigated the effects of UTD2 on the actin cytoskeleton and its critical regulators, and the signaling pathways which are essential for cell motility, growth and survival in MCF-7 breast cancer cells. Results showed that UTD2 inhibited the cellular functions of actin cytoskeleton, such as wound-closure, migration and invasion, as well as adhesion. Our study further demonstrated that UTD2 suppressed Rac1 GTPase activation and reduced the activity of PAK1, which is a downstream effector of Rac1, while the activity of Cdc42 was not affected. Additionally, the phosphorylation of p38 and ERK were significantly inhibited, but the phosphorylation of JNK remained the same after UTD2 treatment. Moreover, UTD2 inhibited the activity and mRNA expression of MMP-2, which plays a key role in cell motility. UTD2 also reduced the phosphorylation of Akt, which is an important signaling kinase regulating the cell survival through Rac1. Furthermore, UTD2 interrupted the synergy between Rac1 and Raf in focus formation assays. Taken together, these results indicated that UTD2 exerted multiple effects on the actin cytoskeleton and signaling pathways associated with Rac1. This study provided novel insights into the molecular mechanism of the antineoplastic and antimetastatic activities of epothilones. Our findings also suggest that the signaling pathways regulated by Rac1 may be evaluated as biomarkers for the response to therapy in clinical trials of epothilones.

• 한국발생생물학회지:발생과생식
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• 제20권1호
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• pp.1-10
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• 2016

Molecular targeting for the altered signaling pathways has been proven to be effective for the treatment of many types of human cancer, including colorectal cancer (CRC). The dual phosphatidylinositol-3-kinase (PI3K) and mammalian target of rapamycin (mTOR) inhibitor BEZ235 has shown to exhibit potent antitumor activity against solid tumors. Autophagy is a cellular lysosomal catabolic process to maintain metabolic homeostasis, which has been known to be induced in response to many therapeutic agents in cancer cells. This process is negatively regulated by mTOR and often acts as prosurvival or prodeath mechanism following cancer therapeutics. The current study was designed to investigate the antiproliferation activity of BEZ235 and to evaluate the role of autophagy induced by BEZ235 using HCT15 CRC cells bearing ras oncogene mutation. We found that BEZ235 decreases cell viability, which was mostly dependent on $G_1$ arrest of cell cycle via suppression of cyclin A expression. BEZ235 affects PI3K/Akt/mTOR signaling pathway by increasing the phosphorylation of AKT at $Ser^{473}$ and RAS/RAF/MEK/ERK pathway by decreasing the phosphorylation of ERK at $Tyr^{204}$. BEZ235 also stimulated autophagy induction as evidenced by the increased expression of LC3-II and abundant acidic vesicular organelles (AVOs) in the cytoplasm. In addition, the combination of BEZ235 with autophagy inhibitor chloroquine, a known antagonist of autophagy, counteracted the antiproliferation effect of BEZ235. Thus, our study indicates that autophagy induced in response to BEZ235 treatment appears to act as cell death mechanism in HCT15 CRC cells.

• 생명과학회지
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• 제23권11호
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• pp.1404-1408
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• 2013

본 연구에서는 마우스 췌장의 선포세포(primary acinar cell)에서 에탄올에 의해 유도된 염증성 손상에 미치는 녹차의 생리활성 물질인 EGCG의 효과를 췌장분비 효소의 활성과 선포세포에서의 기능 회복 관련 마크로 알려진 유전자들(AMPK, RKIP 및 Reg1)의 발현 조절 측면에서 조사하였다. 대조군에 비해 에탄올이 처리된 세포에서는 ${\alpha}$-amylase와 chymotrypsin의 활성이 증가되었지만, EGCG 처리에 의하여 그들 활성이 유의적으로 감소하였다. 세포 생존 및 보호와 관련 있는 AMPK 인산화 수준은 에탄올 단독 처리시 그 발현이 감소하였지만, EGCG 처리에 의하여 유의적으로 회복되었다. 세포 사멸과 세포독성 조절과 연관이 있는 RKIP 또한 그 발현 경향이 AMPK인산화 변화의 정도와 유사하였다. 또한 베타세포 재생에 관여하는 Reg1 발현은 에탄올이 처리된 선포세포에 EGCG를 처리하였을 경우 그 발현량이 유의적으로 증가하였다. 이상의 결과들을 종합하여, 항산화성 폴리페놀인 EGCG는 알코올성 췌장염으로 인한 세포의 손상이나 당뇨병 예방과 회복에 치료적 효과를 가질 수 있다고 제안한다.

• 생약학회지
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• 제45권4호
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• pp.288-293
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• 2014

The present study was conducted to evaluate the hair growth-promoting effect of Clitocybin A from mushroom Clitocybe aurantiaca with dermal papilla cells (DPCs), which play important roles in the regulation of hair cycle. Clitocybin A significantly increased the proliferation of immortalized rat vibrissa DPCs. Flow cytometry analysis revealed that Clitocybin A promoted cell-cycle progression through G0/G1 to S phase in immortalized rat vibrissa DPCs. In addition, Clitocybin A increased the level of cell cycle proteins such as cyclin D1, phospho-pRB, and phospho-CDK2. To elucidate the molecular mechanisms of Clitocybin A on the proliferation of DPCs, we examined the activation of wnt/${\beta}$-catenin signaling which is known to regulate hair follicle development, differentiation and hair growth. Clitocybin A activated wnt/${\beta}$-catenin signaling via the increase of phospho(ser552)-${\beta}$-catenin, phospho(ser675)-${\beta}$-catenin and phospho(ser9)-$GSK3{\beta}$. Furthermore, Clitocybin A markedly increased the activation of extracellular signal-regulated kinase (ERK). These results suggest that the Clitocybin A may induce hair growth by proliferation of DPCs via cell-cycle progression as well as the activation of Wnt/${\beta}$-catenin signaling and ERK pathway.

• 대한임상검사과학회지
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• 제45권2호
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• pp.66-72
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• 2013

Fine Needle Aspiration Biopsy Cytology (FNABC), which is known as the most accurate and cost-effective method for diagnosis of the thyroid nodule, may still result in indeterminate cases that are cellular paucity and show minor nuclear atypia. However, most cases are associated with suspicion of papillary thyroid carcinoma (PTC). A B-type Raf kinase (BRAF) mutation was found in about half of PTCs which is currently helping us to differentiate malignancies from benign lesions. Cases studied included 46 histological, confirmed PTC cases. FNABC 102 cell paucity and 74 atypia benign cases were previously diagnosed as suspicious of PTC using cytologic examination. These cases were analyzed for BRAF mutation by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with a new restriction enzyme. In this study, the sensitivity and specificity were calculated and, BRAF mutation was detected by means of a histological method in 23 of 46 cases of PTC and no mutation was found in 22 cases. However, one case was not detected. In using FNABC, BRAF mutation was detected in 6 of 102 cases in cell paucity and in 11 of 74 cases in the atypia. Two cases were not detected in the atypia. The sensitivity and specificity of PCR-RFLP in FNABC were 60% and 97.4% respectively. Assessment of Formalin Fixed Paraffin Embedding (FFPE) block demonstrated similarly a 51.1% positive and 48.9% negative in PTC. Evaluation of BRAF mutation revealed high specificity and low sensitivity in using FNABC method. This study suggests that BRAF mutation analysis should be useful for the clinical diagnosis of PTC in FNABC with cytological findings suspicious for PTC.

• Genomics & Informatics
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• 제6권4호
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• pp.181-191
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• 2008

RAS guanyl-releasing protein 3 (RasGRP3), a member of the Ras subfamily of GTPases, functions as a guanosine triphosphate (GTP)/guanosine diphosphate (GDP)-regulated switch that cycles between inactive GDP- and active GTP-bound states during signal transduction. Various growth factors enhance hepatocellular carcinoma (HCC) proliferation via activation of the Ras/Raf-1/extracellular signal-regulated kinase (ERK) pathway, which depends on RasGRP3 activation. We investigated the relationship between polymorphisms in RasGRP3 and progression of hepatitis B virus (HBV)-infected HCC in a Korean population. Nineteen RasGRP3 SNPs were genotyped in 206 patients with chronic liver disease (CLD) and 86 patients with HCC. Our results revealed that the T allele of the rs7597095 SNP and the C allele of the rs7592762 SNP increased susceptibility to HCC (OR=1.55, p=0.04 and OR=1.81${\sim}$2.61, p=0.01${\sim}$0.03, respectively). Moreover, patients who possessed the haplotype (ht) 1 (A-T-C-G) or diplotype (dt) 1 (ht1/ht1) variations had increased susceptibility to HCC (OR=1.79${\sim}$2.78, p=0.01${\sim}$0.03). In addition, we identified an association between haplotype1 (ht1) and the age of HCC onset; the age of HCC onset are earlier in ht1 +/+ than ht1 +/- or ht1 -/- (HR=0.42${\sim}$0.66, p=0.006${\sim}$0.015). Thus, our data suggest that RasGRP3 SNPs are significantly associated with an increased risk of developing HCC.

• Asian Pacific Journal of Cancer Prevention
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• 제13권12호
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• pp.6155-6157
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• 2012

Background: Mutations in the MAPK (Mitogen Activated Protein Kinase) signaling pathway - EGFR/Ras/RAF/MEK have been associated with the development of several carcinomas. ERK2, a downstream target of the MAPK pathway and a founding member of the MAPK family is activated by cellular signals emanating at the cell membrane. Activated ERK2 translocates into the nucleus to transactivate genes that promote cell proliferation. MKP - a dual specific phosphatase - interacts with activated ERK2 via the common docking (CD) domain of the later to inactivate (dephosphorylate) and effectively terminate further cell proliferation. A constitutively active form of ERK2 carrying a single point mutation - E322K in its CD domain, was earlier reported by our laboratory. In the present study, we investigated the prevalence of this CD domain E322K mutation in 88 well differentiated OSCC tissue samples. Materials and Method: Genomic DNA specimens isolated from 88 oral squamous cell carcinoma tissue samples were amplified with primers flanking the CD domain of the ERK2 gene. Subsequently, PCR amplicons were gel purified and subjected to direct sequencing to screen for mutations. Results: Direct sequencing of eighty eight OSCC samples identified an E322K CD domain mutation in only one (1.1%) OSCC sample. Conclusions: Our result indicates that mutation in the CD domain of ERK2 is rare in OSCC patients, which suggests the role of genetic alterations in other mitogenic genes in the development of carcinoma in the rest of the patients. Nevertheless, the finding is clinically significant, as the relatively rare prevalence of the E322K mutation in OSCC suggests that ERK2, being a common end point signal in the multi-hierarchical mitogen activated signaling pathway may be explored as a viable drug target in the treatment of OSCC.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7367-7369
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• 2013

Background: Inoperable and metastatic hepatocellular carcinoma (HCC) is associated with a poor prognosis and low chemotherapeutic efficiency. Sorafenib is an oral multi-kinase inhibitor exerting its effects via the RAF/MEK/ERK pathway, vascular endothelial growth factor receptor (VEGFR) and platelet derived growth factor receptor beta (PDGFR-${\beta}$) tyrosine kinases. Randomized studies have shown a significant contribution of sorafenib to life expectancy and quality of life of cancer patients. The aim of the present study is to evaluate the efficacy and side effects of sorafenib therapy in Turkey. Materials and Methods: Data for 103 patients (82 males, 21 females) receiving sorafenib therapy in 13 centers from February 2008 to December 2012 were evaluated. Median age was 61 years and median ECOG performance status was 1 (range: 0-2). 60 patients (58%) had hepatitis B, 15 patients (15%) had hepatitis C infection and 12 patients (12%) had a history of alcohol consumption. All of the patients had Child scores meeting the utilization permit of the drug in our country (Child A). Results: A total of 571 cycles of sorafenib therapy were administered with a median of four per patient. Among the evaluable cases, there was partial response in 15 (15%), stable disease in 52 (50%), and progressive disease in 36 (35%). Median progression-free survival was 18 weeks and median overall survival was 48 weeks. The dose was reduced only in 6 patients and discontinued in 2 patients due to grade 3-4 toxicity, 18 patients (17%) suffering hand-foot syndrome, 7 (7%) diarrhea, and 2 (2%) vomiting. Conclusions: This retrospective study demonstrated better efficacy of sorafenib therapy in patients with advanced HCC compared to the literature while progression-free survival and overall survival findings were comparable. The side effect rates indicate that the drug was tolerated well. In conclusion, among the available treatment options, sorafenib is an efficient and tolerable agent in patients with inoperable or metastatic HCC.